The magnificent Christ Church Spitalfields is a masterpiece of the British baroque and very much an ideal venue for this Spitalfields Winter Festival visit by French period instrument group Le Concert Spirituel. Travelling as a chamber ten-piece without conductor Hervé Niquet, the group performed a selection of early 18th-century works from across Europe, bringing in Muffat, Purcell, Biber, Zelenka, Charpentier, Corelli and Bach.

Goldilocks would not have been a good conductor. There’s a reason why there isn’t a dynamic marking between mezzo forte and mezzo piano. Mezzo on its own would be a pretty bland state of affairs, sat solidly in an inoffensive state of not-too-loud-and-not-too-soft, not swelling to a crescendo or pining away to a decrescendo, but content with a steady sonic compromise. Last night the Orchestra of the Age of Enlightenment gave us a decidedly mezzo Messiah, a performance that couldn’t seem to galvanise itself into any decisive emotion.

Were it not for William Christie and Les Arts Florissants, the vocal and instrumental ensemble he started in Paris in the 1970s, the beauties of the musical French Baroque might have remained a dusty fact of pre-Revolutionary history. As it is, there is barely a singer, player or conductor now performing Lully, Couperin, Rameau, Charpentier et al who has not benefited from the life’s work of this diligent conductor-musicologist. Through him, their arts are indeed flourishing.

What a setting! The history-hopping stealth action series drops into Revolutionary Paris in Unity. Arguably the first game of the "next generation" uses more processing power to render a gigantic, living city teeming with revolting peasants, towered over by Gothic cathedrals and stuffed full of passageways and distractions. Assassin's Creed: Unity looks so real you can almost smell Robespierre's breath. Such a shame, then, that the game fails to engage meaningfully with setting or period.

God-sent sea monsters and divinely ordained human sacrifices don’t wash well with opera updated. The favoured contemporary take on the post-Trojan War myth of Mozart’s Idomeneo, which may even have originated in the last Covent Garden production 25 years ago by a fitfully brilliant Johannes Schaaf, has been to put a populace at risk from natural disaster and pestilence. Clearly the programme was expecting something of the sort, with its images of Hurricane Katrina. But no, for director Martin Kušej, the only monster is the state.

Andrew Graham-Dixon’s villainous alter ego got a second airing tonight in his exploration of 19th-century Britain’s love of all things Gothic. Last week we saw him hanging about in decaying graveyards, or appearing, wraithlike in a dank corner of a Gothic ruin, while ravens circled portentously overhead (main picture). We saw him relating tales of horror and mystery in flickering candlelight, or peering through the flames of an infernal bonfire, and in tonight’s episode, always one for going the extra mile, he was touring Victorian sewers, with only a rat for company.

You may be more familiar with the Italian title, Il mondo della luna, but chances are you won’t have seen this or any of Haydn’s other 16 operas. You haven’t missed much, at least until the last of his works as court composer to the Esterházy family, Armida, an "heroic drama" rather than the slim comedies which don’t seem to have inspired the composer to the heights of his symphonies and string quartets.

To take Figaro – the ultimate operatic assault on class distinctions and social hierarchies – and set it on a giant revolve is a gesture as wilful as it is elegant. Not only are divisions of above and below-stairs dissolved in this steadily circling world, but also those of background and foreground, onstage and offstage. By the time the set’s rotations revealed two young valets with their trousers down, relieving themselves up against a palace wall, some few minutes into the Overture, Fiona Shaw had already won her audience and her case.

What’s the collective noun for mezzo-sopranos? A "warble"? A "might"? A "trouser"? Whatever it is, it doesn’t get a lot of usage outside a choral context. Where in opera would you ever find multiple mezzos sharing a stage? Hardly anywhere. Except, that is, in contemporary castings of baroque operas.

2014 is the 250^th anniversary of the death of Jean-Philippe Rameau, France’s baroque giant and maverick. To say that the UK celebrations have been muted is to put in generously, reconfirming a national trend that has long sidelined this repertoire in favour of more familiar Italian and German contemporaries. So it was especially good to see the Wigmore Hall full for an anniversary concert from instrumental ensemble Les Paladins and soprano Sandrine Piau.